STUDIES OF THE UTILIZATION OF C 14 -LABELED OCTADECENOIC ACIDS BY LACTOBACILLUS ARABINOSUS

Abstract

L. arabinosus was grown in media in which cis-vaccenic-1-C14 acid or oleic-1-C14 acid was supplied in lieu of biotin. The fatty acids present in cells so grown were extracted, separated chromatographically, and examined for radioactivity. It was found that most of the fatty acid removed from a medium during growth could be accounted for by the combined amounts of octadecenoic and lactobacillic acids present in cells grown in that medium. Radioactivity in cellular lipid fractions was limited almost entirely to the same 2 acids. These results indicate that unsaturated fatty acids supplied to L. arabinosus in lieu of biotin are incorporated as such into the cells and there constitute the major cellular content of unsaturated fatty acid. The specific activities of the octadecenoic acid supplied in the medium, cellular octadecenoic acid, and cellular lactobacillic acid were quite similar, suggesting that octadecenoic acid is the precursor of lactobacillic acid. Thise studies provide furthur evidence for the involvement of biotin in the bacterial biosynthesis of certain fatty acids.